Means for measuring current in three-phase systems.



MEANS 'OE MEASURE@ hifi Specification of Letters Patent l eellion iiled January "i, ISDE-. Serial No. @Il ,l

Be it lzlleiln that l1; .in i lillnnn, il eilizen eli' ille United Sintes, i-esicllilke et Chicago, in ille eolllliy e'i Cef' llnll i'lllie el illinois, have illl'ellwl :i :incl llse'flll llnprovelllen in Alien lem-ing Cllilellt ill 'W lume. el which lille fel- ,Sel'llllium i :i nnllnlei' i, mi ll is lleuef--isszliy le lnselli :l l',

l lng' in eliell lie several ilezilzules of .my invention Se fnl' :ls ille/y l'elzll'e L0 the appzu'zlllls er te the eilte-nit arrangement employed lmiy be more readily lilldeni'sleocl by i'elei-enee te ille :leeonlpflnying cli'zlwillgs, in Wliieliligxlye l is a, side elevation, piu-ily in Seetion, el? the elvilieli zlppallins; 2 is a "reni elevation thereof; and F 3 ie li dizigrsnn el the eileniti sind apparatus of my inven li en.

leelll'ed upon ille l of: Slate, i eil-lf E =3 nl" "'el'mii lil upper terminal bleek 2 :nifl a lower 'lei`- ininal bleek 3, suitably spaced apart. Secured upon ille (illpeing faces ei'' the lellninal hleelis :llll'l l lli'e the een'lllei Springs il und 5, leeleci'vely, Snell Springs being ei' the usuel :forni employed for 'the eentuet Springs 0i"'jzlelfia5 llleilf lilee ends being noillilzllly in engagement as Shown in -lull lines in Fig. 1. El. hele (3 ill the base il heilweell the hleelis 2 and lf3 pelnll's of llle inseiion oil" zi plug T of libel' el other insuluiing; inzlelfilih for the pllifllllse nl' separating lille Springs Aly Y: indicated in oiled lines in Fig, l,

,lll eln'vecl eelltzlet Siinil'lg d is in punition le he ellgzlgel by 'ill-e. enfin@ fl when the plug l) in' ililfsel'tecl in the jllel. flfwo el lheee spl-.nge S5 :lle enipleyell7 ene eeipen- :lling n'ill ezlei el die Spi'illesfl- -t 'lziiel spi'ings 8 are nlelllltecl. unen l'lefizelllfzll nungen E) nl; elim-ll, end el" il co'li'elneing hun el.' Siri p lill which ser te eleeiihzzlllj)7 eollnee', smid splil'ln' el: e. .'illd hzll nl? alizlp is nioln'llA- ed upon ille liront lfzleee elf 'lie llleelie lilll: is insulated llel'efioln. ',lflie terminal ilei lliwill be observed than' llie llplllli'ellle inet described pl'evjlrcles twe- )ai l and lllnfee lnllins of the elii'i'eni system. The nmlns .i :unl C :lle

clllel'els 111i. und 1.5, respectively. ille other teinlnlulsei' ssllil Seeelnlul'les :li'e

eonneeted through the conductors 1G und 17j respectively, to n eenlnlell eellclllelm' 1S, which lends 'lo one leiliiillzll of lill illnlneter 1i). The other l'ellnilllil of said al'l'lnietel is eonneel'ed. at 20 with the blu. el strap ll. by a conductor 2l. The Conductor 1S is connected at 22 lio the Strap 10. Il? will thlie be Observed l'lnlt lhe seeenclaiies el the Uillllsfernleis 1Q and 13 ie in pzlrlllleh nelflnzllly elesell lnllnelles of l'he circuit of lhey anlnlelel' IS). Said eillenit lull;Y be l'i'fleenl :1S 'lllllolusz 'lfl'elli the :.llnn'lelel .i9 ll'n'ougli eondlletoi '21 le the 2Os Where the eiienil'. llill'iflee inio tlv( im:

lallel branches, one of which extends through i switches each consisting of spring i'ncmbcrs terminal block 3, springs 5 and 4, conductor 15, transformer 12, conductor 1T to conductor 18. The other branch may be similarly traced through the transformer 13. The common return conductor 18 leads to the other terminal of the ammeter 19. The transformers being thus connected in parallel, the ammeter 19' measures the resultant current of the phases A and C, which resultant equals the current of the phase B. Hence to read the current in phase B the plug is lett out of both jacks J and J.

To read the current in phase A, the plug is inserted in jack Jv, thus opening, at the contact springs l, 5, the parallel branch which includes the transformer 13. Since the ammeter is then in circuit with the transformer 12 only?, it measures the current in phase A. Likewise to measure the current in phase C the plug is inserted in jack J.

t will he observed that as a protection to the transformer, which is located in the branch opened by the insertion of a plug, a short circuit of the secondary thereof is closed when the plug-'is inserted. For example, when the plu is inserted in the aclt J a. short circuit o the transformer 13 is closed from one terminal thereof through the conductor 14, terminal block 2, springs et and 8, strap 10 and conductors 1S and 1o to the other terminal 'ot the transformer 13. ,hus each jaclr comprises two springs #1, 5 normally in Contact but adapted to be spread apart by the insertion of a plug T. lVhen spread apart the spring with contact spring mounted upon a bar l0. common to the spr' lgs 4,4% of both jacks. and short circuits one of the transformers, thus leavin' the noter circuit with the other tran r r -n lily invention is to high tension alter in, which the current brought through )Mael-island iticularly7 adaptable: current systems to be measu ed is strument transtoin'iers to ietf-frs mounted on remote conlt will understood that the arrangement shown and described is susceptible to 'modification without departing from my in,-

normally in contact to connect the trans` ormers in parallel through the instrument, an auxiliary member for cach switch, and a plug for separating said meml ers and simultaneously causing one oif them to malte contact with an auxiliary member to short circuit the corrcspomling` transformer.

'2. The combination with thc mains of a three phase alternating` current system, oi a transformer in two of said mains, an elec-y trical measuring instrument, a pair of switches each consisting' of spring members normally in Contact to connect the transformers in parallel through the instrument, and a plug for separating the members ol each switch.

Circuit controlling mechanism consisting of a switch board, a pair of jacks mounted thereon, each ln'ovidcd with a pair of normally closed sln'ings arranged to be opened by the insertion of a plug in the jack, a har permanently connecting a corresponding spring of each jack, and a second bar extending between said other springs and arranged to be electricallyconnected with either of the same when the plug is inserted in the corresponding jack.

t. Means for measuring the current in each of the phases of a threephase alternating current system, said means comprising a pair of jacks each provided with a pair of normally closed springs arranged to be opened by the insertion ot a plugin the jack, a bar permanently coimecting a ('-orresponding spring ot each jack, a sceonffl bar extend4 ing between said other spri and arranged to be electrically connectml with ciihcrwot the same when the plug is inserted iu the correspondiupl jack, tran iormcrs includ-cd in the circuit ot two ot said phases., each transformer having one terminal ol its scc@ ondary connected to one of said last-mentioned springs. and a measuring instrument having' one oi its terminals eonnecicd to said inist-Ameutioncd har and ils other terminal connected to said second har and o thc other tern'iinals ot the sectmdarics of said transformers.

In 'witness whereof, l, hereunto subscribe my name this Lith day of December Si. D., 1908.

CARL VULR.

ll. E. McEwnN, .intim l. Monitor. 

